ASTM F2129-03

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Designation: F 2129 – 03
Standard Test Method for
Conducting Cyclic Potentiodynamic Polarization
Measurements to Determine the Corrosion Susceptibility of
1
Small Implant Devices
This standard is issued under the fixed designation F 2129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope G 5 Reference Test Method for Making Potentiostatic and
Potentiodynamic Anodic Polarization Measurements
1.1 This test method assesses the corrosion susceptibility of
G 15 Terminology Relating to Corrosion and Corrosion
small, metallic, implant medical devices, or components
Testing
thereof, using cyclic (forward and reverse) potentiodynamic
G 61 Test Method for Conducting Cyclic Potentiodynamic
polarization. Examples of device types that may be evaluated
Polarization Measurements for Localized Corrosion Sus-
by this test method include, but are not limited to, vascular
ceptibility of Iron-, Nickel-, or Cobalt-Based Alloys
stents, filters, support segments of endovascular grafts, cardiac
G 102 Practice for Calculation of Corrosion Rates and
occluders, aneurysm or ligation clips, staples, and so forth.
Related Information from Electrochemical Measurements
1.2 This test method is used to assess a device in its final
form and finish, as it would be implanted. These small devices
3. Terminology
should be tested in their entirety. The upper limit on device size
3.1 Definitions:
is dictated by the electrical current delivery capability of the
3.1.1 potentiostat, n—an instrument for automatically main-
test apparatus (see Section 6). It is assumed that test methods,
taining an electrode in an electrolyte at a constant potential or
such as Reference Test Method G 5 and Test Method G 61 have
controlled potentials with respect to a suitable reference
been used for material screening.
electrode (see Terminology G 15).
1.3 Because of the variety of configurations and sizes of
3.1.2 potentiodynamic cyclic polarization (forward and re-
implants, this test method provides a variety of specimen
verse polarization), n—a technique in which the potential of
holder configurations.
the test specimen is controlled and the corrosion current
1.4 This test method is intended for use on implantable
measured by a potentiostat. The potential is scanned in the
devices made from metals with a relatively high resistance to
positive or noble (forward) direction as defined in Practice G 3.
corrosion.
The potential scan is continued until a predetermined potential
1.5 This standard does not purport to address all of the
or current density is reached. Typically, the scan is run until the
safety concerns, if any, associated with its use. It is the
transpassive region is reached, and the specimen no longer
responsibility of the user of this standard to establish appro-
demonstrates passivity, as defined in Practice G 3. The poten-
priate safety and health practices and determine the applica-
tial scan direction then is reversed until the specimen repassi-
bility of regulatory limitations prior to use.
vates or the potential reaches a preset value.
2. Referenced Documents 3.1.3 scan rate, n—the rate at which the controlling voltage
2
is changed.
2.1 ASTM Standards:
3.2 Symbols:
D 1193 Specification for Reagent Water
3.2.1 E = Breakdown or Critical Pitting Potential—the
b
G 3 Practice for Conventions Applicable to Electrochemical
least noble potential at which pitting or crevice corrosion or
Measurements in Corrosion Testing
both will initiate and propagate as defined in Terminology
G 15. An increase in the resistance to pitting corrosion is
1
This test method is under the jurisdiction of ASTM Committee F04 on Medical
associated with an increase in E .
b
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
3.2.2 E = Rest Potential—the potential of the working
r
F04.15 on Material Test Methods.
electrode relative to the reference electrode measured under
Current edition approved Nov. 1, 2003. Published December 2003. Originally
virtual open-circuit conditions (working electrode is not polar-
approved in 2001. Last previous edition approved in 2001 as F 2129 – 01.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ized).
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.2.3 E = Zero Current Potential—the potential at which
zc
Standards volume information, refer to the standard’s Document Summary page on
the current reaches a minimum during the forward scan.
the ASTM website.
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